PURPOSE: To obtain a highly reliable fuel heating system by providing a junction communicating to the upper and down stream of a fuel pipe in the fuel feed path of Diesel engine while heat producing board and means at the enlarged portion between the junctions.

CONSTITUTION: A conduit member 1 is formed by fastening the large diameter section of a funnel members 1a, 1b through a bolt 2. The first junction 3 is coupled to the upstream side of a fuel pipe while the second junction having small diameter is coupled to the downstream of the fuel pipe. A heat producing member 6 formed with heat producing material is provided in an enlarged section 5 formed between said junctions 3, 4. The heat producing member 6 is held through fastening force of the bolt 2 between the large diameter sections of said funnel members 1a, 1b. Galvanized electrode layers 7, 8 of such as Ni are applied on both faces of said member 6 to be fixed with an electrode board 10. Upon start of engine, voltage is applied to the heat producing board 6 to start heating of fuel effectively and to feed through a path 18 to a fuel filter.